PlantRegMap/PlantTFDB v5.0
Plant Transcription Factor Database
Transcription Factor Information
Basic Information | Signature Domain | Sequence | 
Basic Information? help Back to Top
TF ID AT2G45420.1
Common NameASL20, F4L23.7, LBD18
Taxonomic ID
Taxonomic Lineage
cellular organisms; Eukaryota; Viridiplantae; Streptophyta; Streptophytina; Embryophyta; Tracheophyta; Euphyllophyta; Spermatophyta; Magnoliophyta; Mesangiospermae; eudicotyledons; Gunneridae; Pentapetalae; rosids; malvids; Brassicales; Brassicaceae; Camelineae; Arabidopsis
Family LBD
Protein Properties Length: 262aa    MW: 27218.6 Da    PI: 8.0852
Description LOB domain-containing protein 18
Gene Model
Gene Model ID Type Source Coding Sequence
AT2G45420.1genomeTAIRView CDS
Signature Domain? help Back to Top
Signature Domain
No. Domain Score E-value Start End HMM Start HMM End
       DUF260   1 aCaaCkvlrrkCakdCvlapyfpaeq.pkkfanvhklFGasnvlkllkalpeeeredamsslvyeAearardPvyGavgvilklqqqleqlkaelall 97 
                  +C aCk+lrrkC+++C++apyf +eq ++ fa+vhk+FGasnv+kll ++p ++r+da+ +++yeA+ar+rdP+yG+v++i++lqqq+ +l+ae+++l
                  7***********************998899******************************************************************99 PP

       DUF260  98 kee 100
  AT2G45420.1 135 QAH 137
                  986 PP

Protein Features ? help Back to Top
3D Structure
Database Entry ID E-value Start End InterPro ID Description
PIRSFPIRSF0381276.8E-1391262IPR017394LOB domain-containing protein 18/20
PROSITE profilePS5089122.86636138IPR004883Lateral organ boundaries, LOB
PfamPF031952.9E-3937135IPR004883Lateral organ boundaries, LOB
Gene Ontology ? help Back to Top
GO Term GO Category GO Description
GO:0010089Biological Processxylem development
GO:0010311Biological Processlateral root formation
GO:0005634Cellular Componentnucleus
Plant Ontology ? help Back to Top
PO Term PO Category PO Description
PO:0000084anatomyplant sperm cell
PO:0000290anatomytracheary element
Sequence ? help Back to Top
Protein Sequence    Length: 262 aa     Download sequence    Send to blast
3D Structure ? help Back to Top
PDB ID Evalue Query Start Query End Hit Start Hit End Description
5ly0_A7e-39331387111LOB family transfactor Ramosa2.1
5ly0_B7e-39331387111LOB family transfactor Ramosa2.1
Search in ModeBase
Expression -- UniGene ? help Back to Top
UniGene ID E-value Expressed in
Expression -- Microarray ? help Back to Top
Source ID E-value
Expression AtlasAT2G45420-
Expression -- Description ? help Back to Top
Source Description
UniprotDEVELOPMENTAL STAGE: During lateral root formation, expressed in the lateral root primordia, and the developing, emerged, and mature lateral roots. {ECO:0000269|PubMed:19717544}.
UniprotTISSUE SPECIFICITY: Expressed in roots, stems, leaves and flowers (PubMed:12068116, PubMed:24484953). Expressed in vascular tissues of hypocotyls, leaves, roots, developing floral organs and siliques (PubMed:19088331). {ECO:0000269|PubMed:12068116, ECO:0000269|PubMed:19088331, ECO:0000269|PubMed:24484953}.
Functional Description ? help Back to Top
Source Description
UniProtInvolved in the positive regulation of tracheary element (TE) differentiation. Involved in a positive feedback loop that maintains or promotes NAC030/VND7 expression that regulates TE differentiation-related genes (PubMed:19088331). Functions in the initiation and emergence of lateral roots, in conjunction with LBD16, downstream of ARF7 and ARF19 (PubMed:19717544, PubMed:23749813). Transcriptional activator that directly regulates EXPA14, a gene encoding a cell wall-loosening factor that promotes lateral root emergence. Activates EXPA14 by directly binding to a specific region of its promoter (PubMed:22974309). Transcriptional activator that directly regulates EXPA17, a gene encoding a cell wall-loosening factor that promotes lateral root emergence (PubMed:23872272). Acts downstream of the auxin influx carriers AUX1 and LAX1 in the regulation of lateral root initiation and development (PubMed:26059335). {ECO:0000269|PubMed:19088331, ECO:0000269|PubMed:19717544, ECO:0000269|PubMed:22974309, ECO:0000269|PubMed:23749813, ECO:0000269|PubMed:23872272, ECO:0000269|PubMed:26059335}.
Function -- GeneRIF ? help Back to Top
  1. LBD16 and LBD18 might function in a combinatorial manner in lateral root formation.
    [PMID: 19717544]
  2. E2Fa expression is regulated by the LATERAL ORGAN BOUNDARY DOMAIN18/LATERAL ORGAN BOUNDARY DOMAIN33 (LBD18/LBD33) dimer that is, in turn, regulated by the auxin signaling pathway.
    [PMID: 22003076]
  3. Data show that overexpression of each of the LBD genes promotes callus formation in the absence of exogenous phytohormones, while suppression of LBD function inhibits the callus induction process.
    [PMID: 22508267]
  4. LBD16, LBD29, and LBD18 are involved in cell cycle progression of the pericycle in response to auxin.
    [PMID: 22699776]
  5. This study revealed the molecular function of LBD18 as a specific DNA-binding transcription factor that activates EXP14 expression by directly binding to its promoter.
    [PMID: 22974309]
  6. the proline mutation completely abolished LBD18 DNA-binding activity.
    [PMID: 23430048]
  7. PUCHI co-acts with LBD16 and LBD18 to control lateral root primordium development and lateral root emergence.
    [PMID: 23749813]
  8. Results suggest that LBD18 up-regulates EXPA17 to enhance cell separation to promote lateral roots (LRs) emergence in Arabidopsis.
    [PMID: 23872272]
  9. GBF INTERACTING PROTEIN1 (GIP1) interacts with LBD18 in yeast and Arabidopsis protoplasts. Reverse-transcription-pcr analysis showed overlapping expression of GIP1 and LBD18 in roots, aerial parts, and rosette leaves of Arabidopsis.
    [PMID: 24484953]
  10. Results suggest that Lateral Organ Boundaries Domain16 and 18 (LBD16 and LBD18) are important regulators of lateral root (LR) initiation and development downstream of AUXIN1 (AUX1) and LIKE-AUXIN3 (LAX3) auxin influx carriers.
    [PMID: 26059335]
  11. Data show that the conserved Leu or valine residues in the coiled-coil motif are critical for the dimerization of LBD16 or LBD18 transcription factors.
    [PMID: 28336771]
  12. conserved Leu or Val residues in the coiled-coil motifs of LBD16 and LBD18 are critical for their dimerization as well as the transcriptional regulation to display their biological functions.
    [PMID: 29227192]
  13. uses a dual mode of a positive feedback loop to regulate ARF expression and transcriptional activity
    [PMID: 29681137]
  14. acts downstream of ARF7 and ARF19 in formation of adventitious roots
    [PMID: 30704405]
Binding Motif ? help Back to Top
Motif ID Method Source Motif file
Motif logo
Cis-element ? help Back to Top
Regulation -- Description ? help Back to Top
Source Description
UniProtINDUCTION: By auxin. {ECO:0000269|PubMed:15659631, ECO:0000269|PubMed:19717544, ECO:0000269|PubMed:23749813}.
Regulation -- PlantRegMap ? help Back to Top
Source Upstream Regulator Target Gene
Regulation -- ATRM (Manually Curated Upstream Regulators) ? help Back to Top
Source Upstream Regulator (A: Activate/R: Repress)
ATRM AT5G20730 (A)
Regulation -- Hormone ? help Back to Top
Source Hormone
Interaction ? help Back to Top
Source Intact With
Phenotype -- Disruption Phenotype ? help Back to Top
Source Description
UniProtDISRUPTION PHENOTYPE: Reduced number of lateral roots. {ECO:0000269|PubMed:19717544}.
Phenotype -- Mutation ? help Back to Top
Source ID
T-DNA ExpressAT2G45420
Annotation -- Nucleotide ? help Back to Top
Source Hit ID E-value Description
GenBankAB4738530.0AB473853.1 Arabidopsis thaliana ASL20 mRNA for ASYMMETRIC LEAVES2-like 20 protein, complete cds.
GenBankAF4478910.0AF447891.1 Arabidopsis thaliana LOB DOMAIN 18 (LBD18) mRNA, complete cds.
GenBankBT0257160.0BT025716.1 Arabidopsis thaliana At2g45420 mRNA, complete cds.
Annotation -- Protein ? help Back to Top
Source Hit ID E-value Description
RefseqNP_850436.10.0LOB domain-containing protein 18
SwissprotO221310.0LBD18_ARATH; LOB domain-containing protein 18
STRINGAT2G45420.10.0(Arabidopsis thaliana)
Orthologous Group ? help Back to Top
LineageOrthologous Group IDTaxa NumberGene Number
Representative plantOGRP40515100
Publications ? help Back to Top
  1. Iwakawa H, et al.
    The ASYMMETRIC LEAVES2 gene of Arabidopsis thaliana, required for formation of a symmetric flat leaf lamina, encodes a member of a novel family of proteins characterized by cysteine repeats and a leucine zipper.
    Plant Cell Physiol., 2002. 43(5): p. 467-78
  2. Shuai B,Reynaga-Peña CG,Springer PS
    The lateral organ boundaries gene defines a novel, plant-specific gene family.
    Plant Physiol., 2002. 129(2): p. 747-61
  3. Goda H, et al.
    Comprehensive comparison of auxin-regulated and brassinosteroid-regulated genes in Arabidopsis.
    Plant Physiol., 2004. 134(4): p. 1555-73
  4. Redman JC,Haas BJ,Tanimoto G,Town CD
    Development and evaluation of an Arabidopsis whole genome Affymetrix probe array.
    Plant J., 2004. 38(3): p. 545-61
  5. Okushima Y, et al.
    Functional genomic analysis of the AUXIN RESPONSE FACTOR gene family members in Arabidopsis thaliana: unique and overlapping functions of ARF7 and ARF19.
    Plant Cell, 2005. 17(2): p. 444-63
  6. Soyano T,Thitamadee S,Machida Y,Chua NH
    ASYMMETRIC LEAVES2-LIKE19/LATERAL ORGAN BOUNDARIES DOMAIN30 and ASL20/LBD18 regulate tracheary element differentiation in Arabidopsis.
    Plant Cell, 2008. 20(12): p. 3359-73
  7. Matsumura Y,Iwakawa H,Machida Y,Machida C
    Characterization of genes in the ASYMMETRIC LEAVES2/LATERAL ORGAN BOUNDARIES (AS2/LOB) family in Arabidopsis thaliana, and functional and molecular comparisons between AS2 and other family members.
    Plant J., 2009. 58(3): p. 525-37
  8. Lee DJ,Park JW,Lee HW,Kim J
    Genome-wide analysis of the auxin-responsive transcriptome downstream of iaa1 and its expression analysis reveal the diversity and complexity of auxin-regulated gene expression.
    J. Exp. Bot., 2009. 60(13): p. 3935-57
  9. Lee HW,Kim NY,Lee DJ,Kim J
    LBD18/ASL20 regulates lateral root formation in combination with LBD16/ASL18 downstream of ARF7 and ARF19 in Arabidopsis.
    Plant Physiol., 2009. 151(3): p. 1377-89
  10. Berckmans B, et al.
    Auxin-dependent cell cycle reactivation through transcriptional regulation of Arabidopsis E2Fa by lateral organ boundary proteins.
    Plant Cell, 2011. 23(10): p. 3671-83
  11. Fan M,Xu C,Xu K,Hu Y
    LATERAL ORGAN BOUNDARIES DOMAIN transcription factors direct callus formation in Arabidopsis regeneration.
    Cell Res., 2012. 22(7): p. 1169-80
  12. Heyndrickx KS,Vandepoele K
    Systematic identification of functional plant modules through the integration of complementary data sources.
    Plant Physiol., 2012. 159(3): p. 884-901
  13. Feng Z,Zhu J,Du X,Cui X
    Effects of three auxin-inducible LBD members on lateral root formation in Arabidopsis thaliana.
    Planta, 2012. 236(4): p. 1227-37
  14. Lee HW,Kim MJ,Kim NY,Lee SH,Kim J
    LBD18 acts as a transcriptional activator that directly binds to the EXPANSIN14 promoter in promoting lateral root emergence of Arabidopsis.
    Plant J., 2013. 73(2): p. 212-24
  15. Osakabe Y, et al.
    Osmotic stress responses and plant growth controlled by potassium transporters in Arabidopsis.
    Plant Cell, 2013. 25(2): p. 609-24
  16. Lee HW,Kim MJ,Park MY,Han KH,Kim J
    The conserved proline residue in the LOB domain of LBD18 is critical for DNA-binding and biological function.
    Mol Plant, 2013. 6(5): p. 1722-5
  17. Kang NY,Lee HW,Kim J
    The AP2/EREBP gene PUCHI Co-Acts with LBD16/ASL18 and LBD18/ASL20 downstream of ARF7 and ARF19 to regulate lateral root development in Arabidopsis.
    Plant Cell Physiol., 2013. 54(8): p. 1326-34
  18. Lee HW,Kim J
    EXPANSINA17 up-regulated by LBD18/ASL20 promotes lateral root formation during the auxin response.
    Plant Cell Physiol., 2013. 54(10): p. 1600-11
  19. Lee HW,Park JH,Park MY,Kim J
    GIP1 may act as a coactivator that enhances transcriptional activity of LBD18 in Arabidopsis.
    J. Plant Physiol., 2014. 171(5): p. 14-8
  20. Jin J, et al.
    An Arabidopsis Transcriptional Regulatory Map Reveals Distinct Functional and Evolutionary Features of Novel Transcription Factors.
    Mol. Biol. Evol., 2015. 32(7): p. 1767-73
  21. Lee HW,Cho C,Kim J
    Lateral Organ Boundaries Domain16 and 18 Act Downstream of the AUXIN1 and LIKE-AUXIN3 Auxin Influx Carriers to Control Lateral Root Development in Arabidopsis.
    Plant Physiol., 2015. 168(4): p. 1792-806
  22. Lee HW, et al.
    Dimerization in LBD16 and LBD18 Transcription Factors Is Critical for Lateral Root Formation.
    Plant Physiol., 2017. 174(1): p. 301-311
  23. Pandey SK,Kim J
    Coiled-coil motif in LBD16 and LBD18 transcription factors are critical for dimerization and biological function in arabidopsis.
    Plant Signal Behav, 2018. 13(1): p. e1411450
  24. Pandey SK, et al.
    LBD18 uses a dual mode of a positive feedback loop to regulate ARF expression and transcriptional activity in Arabidopsis.
    Plant J., 2018. 95(2): p. 233-251
  25. Lee HW, et al.
    LBD16 and LBD18 acting downstream of ARF7 and ARF19 are involved in adventitious root formation in Arabidopsis.
    BMC Plant Biol., 2019. 19(1): p. 46